Joshua Goldberg, the fake Aussie jihadist, had a hand in every online fight

Elise Potaka, Luke McMahon, Michael Bachelard

The young Florida man who was arrested after posing as an Australian jihadist was a key player in a large number of online controversies, including the smear campaign against an American black activist who was publicly accused of lying about his race.

Joshua Goldberg, 20, who had been calling for terror attacks in western countries under the guise of jihadist "Australi Witness", was also at the centre of the woman-hating campaigns known as "Gamergate" and a behind a blog called "Philosophy of Rape" on which he wrote that "whores and feminazis need to be put in their place through rape".

On online forums Reddit and 4chan, under the name European88, he uploaded thousands of anti-semitic and racist posts as a neo-Nazi, and on the specialty neo-Nazi site Daily Stormer, he his alter-ego Michael Slay did the same.

After his arrest on terrorism offences on Friday, followed by an investigation and tip-off to police by Fairfax Media, Daily Stormer disavowed him, with site administrator Andrew Anglin writing: "Wacko Jew Terrorist Joshua Goldberg Attempted to Infiltrate the Daily Stormer".

While the journalist has since denied that Goldberg was his only source of information, the emails and tweets indicate that Goldberg at least provided initial assistance.

The lack of real-world verification of Goldberg by journalists and publishers allowed him to gain a public platform. The "Australi Witness" social media accounts were taken at face value by some journalists and intelligence analysts.

Internet users have also been shocked by the Fairfax Media revelation that left-wing "social justice warrior" Tanya Cohen was yet another of Goldberg's multiple personas. Under the guise of Cohen, Goldberg had published articles on a number of well-known sites.

The FBI has charged him over the jihadist accounts, for "distributing information pertaining to the manufacturing of explosives, destructive devices, or weapons of mass destruction in furtherance of an activity that constitutes a Federal crime of violence".

If convicted, Goldberg may be sentenced to a 20-year jail term — a recognition that despite his apparent intentions, he posed a potential real-world threat when he instructed an FBI informant on how to make a bomb with components dipped in rat poison to inflict maximum carnage.

Goldberg's family have said they knew nothing about his internet activities, and neighbours have told US media outlets that he never left the house. Some did not even know he lived there.